1. Field of the Invention
The present invention relates to a method for manufacturing an antenna, and more particularly, to a method for manufacturing an antenna, capable of manufacturing a miniaturized antenna being used in a low frequency band.
2. Description of the Related Art
The recent diversification of mobile communication terminals has led to the release of broadcasting-communication convergence products. Thus, the development of multiplexed, miniaturized and built-in antennas is ongoing. An antenna used for communication performs transmission/reception in a frequency band of 800 MHz to 6000 MHz, and has a size that is small enough to be mounted inside a terminal. However, for broadcasting, the mobile communication terminal currently uses a relatively low frequency band as compared to a frequency for communication. For this reason, it is relatively difficult to mount the antenna within a product. Particularly, in order for the mobile communication terminal to receive a low frequency band of about 86 MHz, even in the case of a λ/4 antenna, the antenna must have a size of at least 85 cm to 90 cm, a size of about 40 cm for a very high frequency (VHF) band, and about 15 cm for an ultra high frequency (UHF) band.
A communication antenna among related art miniaturized antennas is manufactured by injecting a material having a permittivity, or by printing a metallic conductor on a polymer material or a ceramic block having a high permittivity and performing plating thereon. Miniaturized antennas for connectivity are manufactured by stacking ceramic sheets or inserting a conductor in a polymer having a permittivity.
In another method for manufacturing a miniaturized antenna, a composite material which is a mixture of a polymer material for injection and dielectric powder having a high permittivity, i.e., high-k dielectric powder, is injected so as to insert a conductor to a polymer. However, 40 wt % or more of the dielectric power cannot be mixed with the polymer because of the injection process. Thus, there is a limitation in preparing a high-k material.
The composite material for injection developed for a general antenna radiator has a relative permittivity of 20 or less. For this reason, there is a limitation in using the related art composite material for a miniaturized antenna which can be mounted inside a terminal for a UHF band or a lower frequency band.
The high-k composite material used for a related art antenna is developed in order to prevent thermal deformation of high-k ceramics prepared by a thermal treatment, enhance mechanical strength of the ceramics, improve reproducibility of products, and shorten the process time by omitting a thermal treatment process in a manufacturing process. However, when a composite material having a sufficiently high permittivity to miniaturize an antenna is developed, a limitation of a compounding process having the injection process is not overcome. Thus, it is difficult to develop a composite material having a relative permittivity of 30 or higher.